It is one of the central and most enduring elements of the Christmas story – the sighting of a bright star in the skies guiding the Wise Men to Bethlehem and heralding the birth of Jesus Christ.

The Vatican now believes one explanation for the Star of Bethlehem may have been what is known as a ‘Great Conjunction’ of planets, in this case bringing Venus and Jupiter in close alignment and creating an unusually bright light in the sky above the Holy Land.

And the cosmic phenomenon, which could have caused such awe and wonder more than 2,000 years ago, is set to take place once again – just four days before Christmas as it happens.

The closest approach of two planets since 1226 will take place on Monday, December 21, when Jupiter and Saturn come into alignment, creating what astronomers predict will be the marvellous spectacle of an apparently single bright ‘star’.

The alignment of Jupiter and Saturn will occur on Monday, December 21, and will be visible from anywhere on Earth – though conditions will be best near the equator. As Jupiter’s and Saturn’s 12- and 29-year orbits bring them together they will appear low in the western sky.  About 45 minutes after sunset observers should look 10º above the south-southwest horizon to see Jupiter and Saturn shining almost as one.